Tran Walker, 18, of Sioux City, is charged with two counts of first-degree murder.

Around 1 a.m. on Sunday, Walker was in a car with his ex-girlfriend, Paiten Sullivan, 17, and their mutual friend, 18-year-old Felipe Negron Jr. While court documents do not name Sullivan because she was a minor, her name was obtained by the Sioux City Journal.

Walker was upset because Sullivan would not continue their relationship after she ended it, authorities allege. He then stabbed her multiple times in the car at Jay Avenue and South Cecelia Street, police said. When Negron Jr. attempted to intervene, Walker stabbed him multiple times as well, according to court records.

At approximately 1:19 a.m., officers responded to the area for two individuals that were the victims of apparent stab wounds. Both Negron Jr. and Sullivan died as a result of their wounds.

Police were called to Hy-Vee off Gordon Drive around 2 a.m. regarding Walker. He was found with a non-life threatening stab wound, according to Sioux City police.

Walker later admitted to officers that he stabbed both of them and that he wanted his ex-girlfriend "to feel the pain he was feeling," according to court records.